The Triumph Bonneville high beam and low beam headlight bulbs both utilize a 9003 size. The replacement chart covers vehicle production spanning 2001 to 2015.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Triumph Bonneville uses the 9003 bulb size for both high beam and low beam headlights across the 2001-2015 model years.
The 9003 is a dual-filament halogen bulb, meaning a single bulb unit contains two separate filaments: one rated at 60W for high beam operation and one rated at 55W for low beam operation.
Because both beam functions are housed in one bulb, replacing either the high beam or low beam headlight on the Bonneville requires the same 9003 unit.
The 9003 operates on a 12-volt electrical system, which is standard for motorcycle applications in this category.
The 9003 uses a P43t base, which is a bayonet-style mount with a 43mm flange. This base type is specific to the 9003 and its international equivalent, the H4, and is not interchangeable with single-filament base types such as P14.5s or P22d.
The 9003 is defined under ANSI standards and is the North American market designation for what is internationally classified as the H4 bulb. The two designations share the same physical and electrical characteristics, making H4-labeled bulbs a recognized equivalent in fitment references.